US1310795A - Hydraulic press - Google Patents

Description

T. W. HAND. HYDRAULIC PRESS,1SHEABS, AND THE LIKE..

APPLICATION FILED NOV-4,1918.

Patented July 22, 1919.

zlsHEETs-SHEET 1.

T. W.`HAND'. HYDRAULIC PRESS, SHEARS, AND THE LIKE.

APPLICATION FILED Nov. 4. 1918.

1,310,795. 4 Patentedu1y22; 1919.-

2 SHEETS-SHEET 2.

v 'l T ATN rrHOivrAs WIL'ron HAND. OF sHErrIELn, ENGLAND, AssiGNOHTo, DAVY BROTHERS, Lnvirrnn or sHHrrrELD, ENGLAND.

HYDnAULIc ranssfsHnAns, AND THELIKE.

Application filed- November 4, 1918.

To all 'whom t may concern.'

Be it known that I, THOMAS WIL'roN HAND, a subject of the King of Great Britain, residing at Sheilield, in the county of York, England,` have invented new and use- `ful Improvements in Hydraulic Presses,

Shears, andthe like,` of which thefollowing is a specication. y

This invention relates to hydraulic presses, shears, and the like, of the kind wherein the presshead-retracting cylinders and pistons are double-acting, and wherein means are provided for admitting elastic motive fluid (hereinafter, for the sake of convenience, referred to as g steam to one end of said cylinders forthe purpose of retracting the presshead when required, and to the opposite end of said cylinders forv the purpose of eilecting or assisting the preliminary'V or idle portion of a long and comparatively slow working stroke of the press. Thesteam used for retracting the presshead is invariably high-pressure steam, which heretofore (when not used in the form of a permanent elastic cushion acting upon the retracting-pistons) has been exhausted into the atmosphere or otherwise outside the apparatus, and the steam used for effecting or assisting the idle portion of a vworking stroke has also hitherto been high-pressure steam; while, in cases where thehydraulic pressure is derivedffrom a steam hydraulic intensifier, it has been proposed to provide means for economiz-ing steam by exhausting into the steam cylinder of the intensiier the steam used in the retracting-cylinders for effecting or assisting the idle portion of a working stroke, this exhaust steam acting expansivelyupon the intensifier steam piston. v

According to the present invention, which is directed to providing an improved means for effecting economy in the consumption of stea1n,.the movement of the presshead (under gravity or hydraulic pressure as the case may be) during the preliminary or idle portion of a working stroke, is facilitated by the opposite ends of the retracting-cylinders being then put into communication with one another in a close circuit (the supply of high-pressure steam tosaid cylinders being meanwhile cutoff), so that equilibrium of pressures is, for the timebeing, established between the opposite sides of the retracting pistons. Y p t `In the case, foiI example, of a vertically- Specification of Letters Patent,

Patented July 22, 19,19.

Serial No. 261,132.

rendered possible by the invention will de^ pend, primarily, upon the position of the lifting-pistons in their cylinders at the moment referred to; but inasmuch as, under normal working conditions, the lifting-pistons may as a rule be assumed to be, atthat moment, about one third of the total stroke from their lowest position, it will be evident that a considerablel saving of steam will be obtained. Moreover, whatever' the position of the lifting-pistons `when communication is established between the upper and lower ends of the lifting-cylinders, the subsequent expansion of the steam within the closed circuit will take place without the performance of external work, so that the temperature of the steam will tend toremain con-` stant and thus condensation will be reduced to a minimum.

The invention offers a further advantage as compared with arrangements wherein, a permanent cushion of high-pressure steam being maintained beneath the lifting-pistons, high-pressure steam requires to be admitted abo ve` said pistons when it is desired to allow the presshead to descend under gravity; for the 'reason that whereas on the one hand, with such arrangements, the full steam pressure must accumulate in the space above the lifting pistons before the presshead can descend, on the other hand, with the present invention, the presshead will be free to descend as soon as the steam within the closed circuit between the opposite ends of the lifting-cylinders has expanded sufhciently to establish equilibrium of pressures above and cylinders are shown in axial section as is also the valve for controlling` the steam connections appertaining to the lifting cylinders of the press. Fig. 2 is a similar side elevation of the hydraulic press operated by the steam hydraulic intensifier illustrated in Fig. 1, the hydraulic cylinder and the two lifting-cylinders of the press being shown in axial section. Fig. 3 shows separatelyin vertical axial section the piston-valve for controlling the steam connections appertaining to the lifting cylinders of the press, this valve being drawn to a larger scale than in Fig. 1; and Fig. 4 is a detail view illustrating a combined telescopic connection and automatically acting detent and trip mechanism included in the apparatus.

The ram 11 of the press (Fig. 2) reciprocates vertically in the hydraulic cylinder 12 and performs its working strokes in the downward direction; the ram 11 carrying at its lower end the presshead 13, which is fitted to slide on vertical pillars 14 connecting the top plate or entablature 15, whereon the hydraulic cylinder 12 and the steam lifting-cylinders 16 are mounted, with the baseplate 17 which supports the anvil 18. The work 19 is forged upon the anvil by the tool 20 carried by the press head, the upward or return strokes of the tool and presshead being effected by the admission of steam to the lifting-cylinders 16 beneath their pistons 21 which are connected to the presshead 13 by vertical piston-rods 22 fitted to slide through stuffing-boxes 23 in the lower ends of the cylinders 16.

The hydraulic main pressure pipe 24 connects the upper end of the hydraulic cylinder 12 of the press with the lower end of the hydraulic cylinder 25 of the intensifier (Fig. l) and the hydraulic working valve 26, which is interposed in the pipe 24 and adapted to be operated by the handing-lever 27 which controls both the press and the intensifier, serves to govern the connection between the hydraulic main 24 and the air vessel 28 by way of the hydraulic low pressure pipe 29 in the well-known manner of such apparatus.

The ram 30 of the intensifier reciprocates vertically in the hydraulic cylinder 25 and performs its working stroke in the upward direction; the ram 30 carrying at its lower end a cross head 31 which is coupled by vertical side-rods 32 to the piston 33 of the steam cylinder 34 of the intensifier. The hydraulic cylinder 25 of the intensier is placed beneath the steam cylinder 34 and is fixed at 35 to the lower member of a stool or open frame 36 the upper member 37 of which is shown as constituting the bo'ttoniof the steam cylinder 34'; the side rods 32, which are guided at 38 in the lower member of the stool, passing through stufHng-boxes 39 in the bottom 37 of the steam cylinder.

The steam inlet'and exhaust port 40 of the intensifier steam cylinder 34 is connected on the one hand with the main steam supply pipe 41 through the steam inlet valve 42 and on theV other hand with the main steam exhaust pipe 43 through the exhaust valve 44, the valves 42 and 44 (which are to be understood as of the double-beat drop type) being controlled both manually and automatically.

For this purpose thev vertically-slidable spindles of the inlet valve 42 and exhaust valve 44 are coupled respectively to different points in the lengthv of a floating lever 45 which on the one hand is connected, through a lever 46 fulcrumed at a fixed point 47, and through a rod 48, to an arm 49 moving as one with the handing-lever 27 about the fulcrum 50 of the latter; the iioating lever 45 being on the other hand connected, through a lever 51 fulcrumed at,

a fixed point 52, and through a rod 53, to an arm 54 moving as one with a lever 55 which is fulcrumed at a fixed point 56. The lever 55 carries at its extremity a roller 57 which is held by a counterweight 58 in contact with the inclined edge 59 of an upright upwardly-tapering cam-bar-GO fixed to and extending upward from the cross head 31; the opposite edge of this cam-bar extending parallel with the direction ofmovement of the ram 30 and piston 33 and'being guided by contact with a stationary roller 6l. The arrangement is such that, in whatever angular position the handinglever 27 is held so as, by opening the steam inlet valve 42, to cause steam to be admitted to the cylinder 34 and thus raise the piston 33, the valve 42 will be automatically closed on the piston reaching that point in its stroke which corresponds to the angular position occupied for the time being by the lever 27 the operation of the intensifier being thus kept under the control of the handing-lever in such manner that any risk of excessive upward movement of the steam piston 33 is automatically prevented. i I

The steam connections to the lifting-cylinders 16 are controlled by a verticallyworking `piston-valve 62 (Figs. 1 and 3) hereinafter referred to as the lifting-cylinder' valve, which is actuated by the handinglever 27. The casing of the valve 62 has (see Fig. four sets of ports at different levels; the lowest set of ports 63 being connected by a branch `64 to the main steam supply pipe 41, While the highest set of ports 65 are Vconnectedby a pipe 66 to the mainsteam exhaust. pipe 43. Of Vthe two intermediate sets of ports, the upper set 67 are connected by a pipe 68 and `branches 69 and 70 to the upper ends of the respective lifting-cylinders 16; while the lower set 71areA connected by a pipe 7 2 and branches 73 and 74 to the lower end of the respective liftingcylinders. The valve-piston` has two cylindrical faces 75 and 76 separated by a waistportion 77 of reduced diameter; the lengths of the faces 75, 7 6, and their distance apart, being such that, so long as the valve-piston rests in its normal or lowest position (as in Figs. 1 and 3) the ports 63 and 71 are connected, and the ports 65 and 67 are also connected but at the same time separated from the ports 63 and 71, so'that on the one hand steam is admitted from the main steam supply pipe 41 (by way of the branch 64, ports 63 and 71, pipe 72, and branch pipes 73 and 74) to the lower ends of the lifting-cylinders 16, and on the other hand communication is opened from the upper ends of the cylinders `16 (by way of the branch pipes 69 and70, pipe 68, ports 67 and 65, 'and branch pipe 66) to the main steam exhaust pipe 43; whereas, when the valve-piston occupies an intermediate position, both the steam port 63 and exhaust ports 65 of the valve are, closed, and communication is established between the lower and upper ends of the lifting-cylinders 16 (by way of the branch pipes 73 and 74, pipe 72, ports y71 and 67, pipe 68, and branch pipes 69 and 70) between the lower and upper ends of the lifting-cylinders 16.

The valve- piston 75, 76, 77 is attached to a weighted lspindle 78 which, passing out through a stuffing-box at the end of the valve-casing, is connected, through a combined telescopic joint and automaticallyacting detent-and-trip mechanism of known construction indicated at 80, with` a rod 79 permanently attached to `the lever 46. As

shown in Fig. 4 the rod 79 is slidable in the.

sleeve 8O and is provided with a recess a at an intermediate point. A latch bolt b is iitted to slide transversely through an aperture in the sleeve 80 and is normally pressed inwardly by spring c. Abell crank lever cl is pivoted upon the sleeve 80- and has its one end connected withthe latch bolt b and its other end -pivotally connected with one end of a link c. The other end of said link is slotted as at f and is slidably connected with a rigid stop g located on `the valve casing 62.`

So long as the handing-lever 27, lever 46, and piston-valve 75,. 76, 77 occupy substantially the position shown, the telescopic joint permits free movement of` the rod 7 9` inv the sleeve y80; relatively to the valve-spindlel 7 8 in either direction within predetermined limits, that is within those limits in which the recess a does not register with the latch bolt b. When however the handing-lever 27 isl angularly displaced toward the left so as to depress the lever 46 and rod 79 beyond a certain limit or, in other words, until the latch bolt b snaps into the recess a, the valve-spindle 78 becomes automatically engaged with the rod 79. When the handinglever is returned toward the right, the valvepiston 75, 76, 77 is raised along with the lever 46 until, on the valve-piston passing upward beyond the intermediate position already referred to, the yvalve-spindle 78 becomes automatically disengaged from the rod 79 so that the valve-piston is free to fall back to its lowest position. This disengagement takes place because the upward travel of the link is stopped when the lower end ofv its slot f engages the stop g and thus swings the bell crank lever Z in a direction to retract the latch bolt b from the recess a against the tension of the spring c.

From the foregoing it will be seen, first, that so long as the valve-piston 75, 7 6, 77 is in its normal or lowest position, a cushion of high-pressure steam will be maintained .in the lifting-cylinders 16 beneath the pistons 21, which will accordingly (assuming other conditions to be favorable) tend to rise and lift the presshead 13 and ram 11, owing to the absence of steam pressure above the pistons 21 in consequence of the upper ends of the cylinders 16 being open to the exhaust pipe; secondly, thatwhen the valvepiston is raised from the lowest to the intermediate position, high-pressure steam will no longer be able to gain access to the cylinders 16 beneath the pistons 21, while the st eam already beneath these pistons will be allowed to pass from the lower to the upper side of the pistons and will expand until, equilibrium of pressures being established on the opposite sides of the lifting-pistons, the press-head 13 and ram 11 (if previously raised) will be free to descend under gravity; and thirdly, that thevalve-piston, when further raised to the level at which it is released from the lever 46,will automatically return to the lowest position, thus restoring the cushion of high-pressure steam beneath the lifting-pistons 21 while `allowing the expanded steam above said piston to become exhausted so that (other conditions being favorable) the presshead 13 and ram 11 will again tend to rise.

The working-valve 26, the construction and operation of which are fully described in the specification already referred to, is controlled (as previously stated) by the handing-lever 27; for which purpose the arm 49 of the handing lever is coupled by a rod 81 to a lever 82 which acts upon the spindle of; the working-valve. This valve,

which normally cuts ofi communication between the air vessel 28 and 'the hydraulic main pressure pipe 24, is adapted, when open, to permit water to fiow from the pipe 24 to the air vessel or vice versa according to circumstances; the opening cf the valve being produced by means of the handing-lever 27 when it is required to reduce the quantity of water in the pipe 24 and cylinders 11 and 25, but being effected automatically when it is required to fill up the vacuum created in the pipe 24 and cylinders 11 and 25 by the idle descent of the rams 11 and 30 or either of them.

The operation of the apparatus as a whole will now be described; it being understood that, during resting conditions (i. e. with the handing-lever 27 standing in the mid position shown, the steam valve 42 and the exhaust valve 44 of the intensifier both closed, the piston of the lifting-cylinder valve 62 occupying its lowest position, the workingvalve 26 closed, the steam piston 33 and hydraulic ram 30 of the intensifier at the bottom of their travel, and the tool 2O of the press resting either on the anvil 18 or work 19), the presshead will not rise although steam be admitted to the pipe 41 so as to gain access beneath the pistons 21of the liftram 11 sufficiently either to accommodate the ing cylinders 16, the reason being that the hydraulic main pressure pipe 24, as well as the hydraulic cylinders 12 and 25, are all filled with water.

` If, now, it be desired to set the press in operation, the water in the pipe 24 must first be afforded freedomto escape so as to enable the pistons 21 to raise the presshead 13 and work on the anvil or to enable a working stroke of the tool 20 to be performed.

For this purpose the handing-lever 27 must be mioved toward the left so as to cause the lever 82 to open the working-valve 26; the steam pressure beneath the lifting-pistons 21 being thus enabled to raise these pistons owing to the surplus water, expelled from the cylinder 12 and pipe 24, being now permitted to pass by way of the pipe 29 to the air vessel 28.

This movement of the handing-lever 27 toward the left depresses the lever 46, it being understood that this is permitted by the telescopic connection at 80 between the lever 46` and valve spindle 78.

The nature of the subsequent operations, all of which are controlled by the single handinglever 27, will depend upon whether it is desired to work the press with long and comparatively slow strokes, or with short and quick strokes. If short, quick strokes are required, a cushion of high-pressure steam must be maintained beneath the lifting-pistons 21; and in order to insure this, the oscillations manually imparted to the handinglever (for the purpose of actuating the valves 42 and 44 so as to bring about successive strokes of the piston 33, ram 30, and ram 11) must be kept within the limits of that are of its throw wherein the rod 79 fails to descend so far as to become engaged with the valve spindle 78. As, in these circumstances, the valve-piston .75, 76, 77 will remain resting in its lowest position, not only will steam gain access uninterruptedly to the earlier part of each downward stroke of the ram 11, so as to allow thisl rain and the presshead 13 to drop by gravity and prevent them from rising before the pressing portion of the stroke commences on the tool 20 encountering the work 19. For this purpose, at the commencement of each long working stroke of the press, the handing-lever 27 must be moved over to, or near, the left-hand limit of its throw so as to insure the rod 79 becoming engaged with the valve-spindle 78 in the manner hereinbefore described, with the result that, on the handing-lever being thereafter moved toward the right, the valve- piston 75, 76, 77 will be raised to its intermediate position wherein lit permits the steam imprisoned beneathv the lifting-pistons 21 to expand into the upper ends of the cylinders 16, thus establishing equilibrium of pressures above and beneath the pistons 21.

This upward movement of the valve- piston 75, 76, 77 continues until the trip mechanismy at 8O bringsabout the disengagement of the valve-stem 78 from the rod 79 as previously described and the consequent return of the valve-piston to its lowest position, which'happens at about the moment when the han ding-lever 27 reaches that angular position whereat the steam inlet valve 42 of the intensifier begins to open.

The dropping of the valve-piston 75, 7 6, 77 at or about this moment insures the provision of a cushion ofhigh-pressuire steam beneath, and the absence of steam pressure above, the lifting-pistons 21 in time to cause the presshead 13 and ram 11 to rise promptly at the termination of the long pressing stroke. c

In the foregoingdescription, the elastic motive Huid operating in the intensifier and in the liftingcylinders of the hydraulic press is for the sake of convenience referred to as steam, but it will be evident that other elastic motive fluid (such as Vcompressed air for example) may be used; and

hence 'it is to be understood that both throughout the description and in the appended claims the term fst-sam is `to be interpreted as including any kind of elastic motive fluid.

1; The combination of a hydraulic press, Iincluding` a. press-head, a steam, hydraulic intensifier for actuating said press, a single operati ng; lever for controllingsaid press and intensifier in common, `a press-head retracting cylinder, a. ydouble acting piston therein .operatively connected with said press-head, a piston-valve casing havin-,g a live steam connection and an exhaust, alive steam connection from said casing to one end of said press-head retracting cylinder, an exhaust steam connectionfrom said casing to the other end of said cylinder, said last two'connections being arranged to constitute a steam inter-connection between the respective ends of said retractinp; cylinder through said casing, a piston-valve in said casing contro-lling all of said steam connections in common, said piston valve, tending constantly to assume anormal position wherein the ends of the retracting-cy-linder are open respectively to the live steam supply and to the exhaust, and a connection between the piston-valve and the operating lever whereby the normal position of the piston-valve is undisturbed as long as the press is worked with short and rapid strokes and whereby, when said press is worked with `long and slow strokes said piston-valve is actuated to cut off the retracting cylinder from both the live steam supply and the exhaust, and to put the opposite ends of said cylinder into communication with each other, at the commencement and during the earlier part of each long stroke.

2. In hydraulic pressure-utilizing apparatus, the combination of a hydraulic cylinder, a ram fitted to reciprocate therein, means for admitting hydraulic pressure to said cylinder for causing the ram to perform its working stroke, an elastic fluid cylinder, a double-acting piston fitted to reciprocate therein and connected to said ram, a passage for admitting high-pressure elastic motive fluid to one end of saidelastic fluid cylinder for yproducing retractive movement of the ram, a passage for discharging elastic motive fluid from the other end of said elastic fluid cylinder to exhaust, and means for opening both of said passages concurrently during such retractive movement and, alternatively, connecting said passages together in a closed circuit during the idle portion of a working stroke of said ram, for the purpose set forth.

3. In hydraulic pressure-utilizing apparatus, the combination of a hydraulic cylinder, a ram fitted to reciprocate vertically therein and adapted to perform its workhaust, and means for opening both of said passages to effect the upward stroke of the hydraulic ram and, alternatively* connecting1 :said passages `together in a closed circuit to assist the downward stroke of the ram.

l. `In yhydraulic pressure-utilizing appa- I ratus, the combination of a hydraulic cylinder, a ram fitted to reciprocate vertically therein, and adapted to perform its working stroke in the downward direction, an elastic fluid cylinder, a double-acting piston fitted to reciprocate vertically therein and connected to said ram, a passage leading from a source of high-pressure elastic motive fluid supply to the lower end of said elastic fluid cylinder, a passage leading from the upper end of the same cylinder to exhaust, and a piston-valve interposed in said passages and adapted, when the valve-piston occupies one position to open both passages and, when the valvepiston occupies another position, to connect the passages together in a closed circuit, for the purpose set forth.`

5. The combination, with liydraulic pressure-pro ducing apparatus comprising a steam cylinder, a piston fitted to reciprocate ver'- tically therein, a hydraulic cylinder, a ram fitted to reciprocate vertically therein and coupled to said piston so as to move as one therewith, passages for admitting steam to and exhausting it from said steam cylinder, valves on said passages, and a lhandinglever for actuating said valves, and with hydraulic pressure-utilizing apparatus comprising a hydraulic cylinder, a ram fitted to reciprocate vertically therein, a pipe-connection between the respective hydraulic cylinders, a steam cylinder, a double-acting piston fitted to reciprocate vertically therein and coupled to the last-mentioned ram, and passages leading respectively from a source of high-pressure steam supply to the lower end of the last-mentioned steam cylinder and from the upper end of the same cylinder to exhaust, of a piston-valve interposed in the last-mentioned passages, and a combined telescopic joint and automatically-acting detent-and-trip mechanism for detachably engag-ing the piston of said piston-valve with the handing-lever, the piston-valve being adapted alternatively, to open both of said last-mentioned passages and to connect said passages together in a closed circuit, substantially as and for the purpose set forth.

6. The combination with hydraulic pressure-producing apparatus comprising a steam cylinder, a piston fitted to reciprocate vertically therein, a hydraulic cylinder, a ram fitted to reciprocate vertically therein and coupled to said piston so as to move as one therewith, passages for admitting steam to and exhausting it from said steam cylinder, valves on said passages and a handing-lever for actuating said valves, and with hydraulic pressure-utilizing apparatus comprising a hydraulic cylinder, a ram fitted to reciprocate vertically therein, a pipe-connection between the respective hydraulic cylinders, an air vessel, a branch-pipe from said pipe-con nection to the air vessel, a valve on said branch-pipe coupled to the handing-lever, a

steam cylinder, a double-acting piston iitted to reciprocate vertically therein and coupled to the last-mentioned ram,I and passages leading respectively from a source of highpressure steam supply to the lower end of the last-mentioned steam cylinder and from the upper end of the same cylinder to eX-y haust, of a piston-valve interposed in the last-mentioned passages, and a combined telescopic joint and automatically-acting detentand-trip mechanism for detachably engaging the piston of said piston-valve with the handing-lever, the piston-valve being adapted, alternatively, to open both of said last-mentioned passages and to connect said passages together in a closed circuit, substantially as and for the purpose set forth.

THOMASy VILTON HAND.

Copies of this patent may be obtained for five cents each, 'by addressing the Commissioner of Patents,

f Washington, '.D. C.

Images